Jamaican flora and fauna. Engraved page depicting Jamaican worm grass (Spigella anthelmia) and a cockroach. Worm grass is a poisonous tropical annual weed growing to around 30cm tall. It contains an alkaloid called spigeline that acts on the heart. In dilute form it has been used as a traditional medicine in many countries around the Caribbean Sea. Cockroaches are insects of the order Blattaria, of which there are some 4500 species. This engraving first appeared in Gentleman's Magazine in 1751.